(10-15) 16:54 PDT ANTIOCH -- A man and a woman from San Francisco were shot and killed Sunday evening in an unincorporated area near Antioch, authorities said.

The victims - identified as Christopher Zinn, 24, and Brieanna Dow, 21 - were found on Buchanan Road near Somersville Road about 5:25 p.m., said the Contra Costa County Sheriff's Office. The circumstances of the shootings are unclear.